Masonry Veneer Curtain Walls
20 Cladding With Masonry and Concrete Masonry Veneer Curtain Walls Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Construction Sequence and Essential Elements • Shelf angle is installed on the structural frame • Soft joint or horizontal expansion joint is maintained below the shelf angle • Flashing is installed over the shelf angle and it should project by 1” (25mm) and should be bent downward at a 450 angle. • Flashing is tucked into the backup wall or over the slab Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Construction Sequence and Essential Elements • A back up wall of concrete or steel studs covered with water resistant sheathing panels of gypsum or cementitious material is constructed • A weather barrier and air barrier are installed over the backup wall followed by insulation • Brick masonry veneer wythe is erected brick by brick or stone by stone with conventional mortar and tied to the backup wall by ties Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Shelf Angles & Horizontal Joints 1. 2. 3. Shelf angle attached to a concrete frame with an insert cast into the slab Shelf angle attached to a steel frame using clip angle and shim plate and wedge shaped slot for adjustments Soft joint or horizontal expansion joint is shown in the typical detail of brick veneer cavity wall with concrete block backup wall. Joint is designed to absorb column creep, brick expansion, spandrel beam deflection and dimensional tolerances 2 3 1 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Vertical Joints • Masonry curtain walls must be divided vertically by movement joints called vertical expansion joints to allow the frame and the masonry cladding to expand and contract independently of one another Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Backup Walls and Structural Frames Detail and Completed Building – Brick Veneer With Steel Stud Backup With Steel Structural Frame • Backup walls may be of concrete or steel studs • Masonry cavity wall may be installed on buildings with structural frames of concrete or steel. Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Prefabricated Reinforced Brick Panel Curtain Walls 1. 2. 2 Masons construct the panels while working comfortably at ground level in a factory. Horizontal and vertical reinforcements are laid as required Panels are self-rigid and need no structural backup 1 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Masonry Veneer Curtain Walls Prefabricated Reinforced Brick Panel Curtain Walls • These panels can be fastened to the building in much the same way as precast panels • A steel stud backup wall is required to carry thermal insulation, electrical wiring, and an interior finish layer but has no structural role Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 20 Cladding With Masonry and Concrete Stone Curtain Walls Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Stone Curtain Walls Stone Panels Mounted on a Steel Subframe • Grid-system-supported stone cladding – – – – – Vertical members are erected first to transmit gravity and wind loads The horizontal members are aluminum shapes that engage in slots in upper and lower edge of each stone Backer rods and sealants fill the joints between the stone Non structural back-up wall of steel studs and gypsum sheathing is constructed within the frame of the building to provide air barrier, insulation, electrical wiring and interior finishes Sealant joints are the weak link for water penetration Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Stone Curtain Walls Stone Panels and Extruded Aluminum Supports 2 • Stone cladding installation in progress 1. The reddish orange material is the weatherresistive membrane. If properly sealed at its seams and edges, this product is also capable of acting as an air barrier 2. Vertical lines struck on the membrane mark the locations of metal studs in the backup wall. Anchor fasteners must be located over these lines, so that they engage the studs 2 1 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 2 Stone Curtain Walls Stone Panels and Extruded Aluminum Supports • Anchor close-up. Note the resilient cushioning material where the anchor is slotted into the stone • This image also illustrates several construction deficiencies: 2 1. The fasteners appear to be offset so far to one side of the anchor and its shims that the clip may not remain stable when fully loaded by the weight of the next panel above 2. The continuity of the weather-resistive/air barrier has been interrupted by electrical conduit routed in the space behind the stone Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 1 Stone Curtain Walls Monolithic Stone Cladding Panels • The panels are fastened directly to the frame of the building • The weight is transferred to two steel support plates by means of edge pockets that are cut into both sides at the stone mill • Each panel is stabilized by a steel angle strut • Joints are closed with backer rod and sealant • A non structural backup wall is required Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Stone Curtain Walls Stone Cladding on Steel Trusses • Sheets of stone are combined into large prefabricated panels by mounting them on structural steel trusses • Each truss is designed to carry wind loads and dead load of the stone to steel brackets that are used to attach the truss to the building frame • This is a relatively costly system Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Stone Curtain Walls Posttensioned Limestone Spandrel Panels • Thick blocks of limestone may be joined with adhesives into long spandrel panels and post-tensioned with strength steel tendons • The assembly is self supporting between columns • This is a relatively costly type of panel Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Stone Curtain Walls Very Thin Stone Facings • Extremely thin sheets of stone may be stiffened with a structural backing such as a metal honeycomb and mounted as spandrel panels in in an aluminum mullion system • Very thin sheets of stone may be used as facings for precast concrete curtain wall panels • When specifying the thicknesss of stone for any exterior cladding application, the designer should work closely with stone supplier. • Thin stones have been a cause of number of failures of cladding systems Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 20 Cladding With Masonry and Concrete Precast Concrete Curtain Walls Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Precast Concrete Aesthetics • Precast concrete cladding panels can be conventionally reinforced and be prestressed • They can come in variety of sizes and surface finishes, from glassy smooth to rough, exposed aggregates • Ceramic tiles, thin bricks or stone facings may be attached to precast panels Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Precast Concrete Manufacture of Sandwich Panel 1. 2. 2 Ribbed surface finish being applied to precast concrete before the concrete sets Insulation can be incorporated into the precast concrete panel in a sandwich panel system 1 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Typical Detail of Precast Concrete Curtain Wall • Precast on sitecast concrete frame • Panels shown are full story high containing a fixed window. Bottom half of one panel (1) and top half of the lower panel (2) are shown • The reinforcing bars are omitted for clarity but outline of thermal insulation and interior finishes (3) on the interior is shown 3 1 2 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Precast Concrete Cladding Installation • Precast concrete spandrel panels and brick veneer column covers hung off of a cast-in-place concrete frame structure Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Precast Concrete Cladding Installation • End view of a precast concrete spandrel panel • Two polyisocyanurate rigid foam insulation boards (1) are visible on the back of the panel. • The slightly darker colored band of insulation (2), at slab level between the two insulation boards, is safing, intended to restrict the passage of smoke and fire between floors. Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 1 2 1 Precast Concrete Curtain Walls Glass-Fiber-Reinforced Concrete Curtain Walls Fabrication • GFRC is a relatively new cladding material • Its admixture of short glass fibers provides enough tensile strength that no steel reinforcing is required • Panel thickness and weight are about one quarter of those for precast • They can be molded into variety of shapes • The panels may be self-stiffened with GFRC ribs but the usual practice is to attach a welded frame of light gauge steel studs to the back of GFRC Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Precast Concrete Curtain Walls Glass-Fiber-Reinforced Concrete Curtain Walls Attachment 1. 2. 3. GFRC panels can be attached with a diagonal brace and downrigger GFRC panels can be attached with angle with oversized hole Steel rod anchors can flex to accommodate small amounts of movement between the facing and the frame 1 2 3 Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 3 Precast Concrete Curtain Walls Glass-Fiber-Reinforced Concrete Curtain Walls – Joint Treatment • Edges of the GFRC panels are flanged to provide surface for sealant at joints • Edge of the GFRC panels at transition between components need to be designed for receiving membrane and cap flashing Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 20 Cladding With Masonry and Concrete Exterior Insulation and Finish Systems Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Exterior Insulation and Finish Systems EIFS – Essential Elements • Exterior insulation and finish system (EIFS) consists of – – – – Layer of plastic foam insulation adhered or mechanically fastened to a backup wall A reinforcing mesh that is applied to the outer surface of the foam A base coat of a stucco like material which embed the mesh An exterior finish coat of a similar stucco like material that is troweled over the base coat Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Exterior Insulation and Finish Systems EIFS – Panelized System • • EIFS can be constructed in place over a backup of concrete masonry or steel studs EIFS can also be prefabricated A. B. C. Steel studs are welded together to make a backup frame Rigid sheathing is screwed to the frame and finished with EIFS The finished panels are lifted and bolted to the building frame Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Exterior Insulation and Finish Systems EIFS – Drained Systems • EIFS typically is designed as a barrier type system which has resulted in numerous cases of water damage in EIFS faced buildings • EIFS producers now market water managed or waterdrainage EIFS – These systems utilize a layer of drainage matting behind the foam insulation that can capture water and conduct it to plastic flashings and weeps at the base of the walls Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 20 Cladding With Masonry and Concrete Future Directions in Masonry and Stone Cladding Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. Future Directions in Masonry and Stone Cladding Need For Rainscreen Systems • Most masonry and concrete cladding systems except brick veneer are barrier systems • There is no well organized system of secondary drainage • There are cavities behind these systems but are interrupted by framing and attachment components • There have been isolated efforts to design true rain screen details for stone and concrete cladding systems but more research is needed Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. All rights reserved. 20 Cladding With Masonry and Concrete MasterFormat Sections For Masonry and Concrete Cladding CSI/CSC MASTERFORMAT SECTIONS FOR MASONRY AND CONCRETE CLADDING 03 40 00 PRECAST CONCRETE 03 45 00 Precast Architectural Concrete Faced Architectural Precast Concrete 03 49 00 Glass-Fiber-Reinforced Concrete 04 20 00 UNIT MASONRY 04 21 00 Clay Unit Masonry Brick Veneer Masonry 04 25 00 Unit Masonry Panels Metal-Supported Unit Masonry Panels 04 40 00 STONE ASSEMBLIES 04 42 00 Exterior Stone Cladding Grid-System-Supported Stone Cladding Stone Panels for Curtain Walls 07 20 00 THERMAL PROTECTION 07 24 00 Exterior Insulation and Finish Systems Polymer-Based Exterior Insulation and Finish System Polymer-Modified Exterior Insulation and Finish System Water-Drainage Exterior Insulation and Finish System 07 40 00 ROOFING AND SIDING PANELS 07 42 00 Wall Panels Fabricated Wall Panel Assemblies Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 John Wiley & Sons. 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